Embodiments of the subject matter disclosed herein generally relate to a guide funnel for guiding a subsea infrastructure, for example, a Christmas tree, a lower riser package (LRP) or a blow-out preventer (BOP), for the purpose of connection with a subsea wellhead or mandrel profile, and to a method of connecting a subsea infrastructure to a subsea wellhead or mandrel profile.
Guide funnels are well-known for guiding a subsea infrastructure, such as a Christmas free, for the purpose of connecting with a subsea wellhead. Such guide funnels may comprise an upwardly facing funnel on the wellhead to guide and receive the lower end portion of the tree as the tree is lowered into a vertically aligned position with the subsea wellhead. Such upwardly facing guidance funnels are suitable for use with conventional vertical trees, as these tend to have robust connectors at the bottom end for connection to the wellhead, which can easily withstand vertical impacts associated with the installation of the tree on the wellhead.
However, horizontal trees often contain more fragile connectors at the bottom end which must be aligned with the wellhead and which can be easily damaged if not properly aligned. In order to avoid damage to the tree connectors it is common to provide a downwardly facing funnel on the tree body around the connector for guiding the tree into correct alignment with the wellhead.
Industry standard ISO 13628-4:2010 specifies a minimum acceptable vertical alignment of 3 in guidance funnels for subsea wellhead and tree equipment. In accordance with the guidelines the height of the guidance funnel may be a significant proportion of the overall assembly height. Such large funnels have been found to impact on the transportation and deployability of trees, or other such equipment.
It is the object of the embodiments of the present invention to overcome some of the problems of the prior art, or at least to offer an alternative to currently available guidance funnels.